Mobile devices are widely used for various applications. Some mobile applications, for example, those designed for reading and writing email messages, messages for social networks, banking, and payment processing, may require a high level of confidence that the mobile device is being used by its owner. In other applications, for example, in those designed to take pictures or browse public internet pages, there may be no need for such a high level of confidence.
One of the conventional solutions to ensure the mobile device is in possession of its owner is to lock the mobile device if it has not been used for a pre-determined period of time. Then, the owner of the mobile device can be asked to provide login credentials each time he or she wants to regain access to the mobile device. For example, the owner can be asked to enter the user password or asked for a fingerprint to be taken. This conventional approach may be very inconvenient in some situations, for example, when the user needs to take a photo to capture some fleeting moment that would be otherwise lost if time had to be taken first to provide user credentials or have a fingerprint taken. There is also the inconvenience associated with needing to reenter credentials or have a fingerprint taken even though the mobile device has remained in the user's possession for longer than the pre-determined period for locking of the mobile device.